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Full text of "The Cambridge Natural History"

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than some Gorillas. But the average is undoubtedly as stated,
It is to be noted that there is a correspondence between cranial
capacity and size of palate, the correspondence "being converse, i.e.
the greater the "brain the smaller the palate. This applies to
Man as compared with his Ape-like relatives, but does riot apply
so accurately to the Gorilla, which has a more extensive palate
than the Chimpanzee ; its " brute development " is much greater
than that of the Chimpanzee. Not only is the palate larger, but
the molar teeth, slightly different in form, are also larger and
stronger. This is so plainly marked that " one may say almost
with certainty, that any upper molar tooth over 12 mm. in
length is that of a Gorilla, and under 12 mm. is that of a Chim-
panzee." In the skeleton generally it may be said that the
crests for muscular attachments upon the bones are greater in
the Gorilla. The nasal bones are more like those of lower Apes
in their length, and they have a sharp ridge more marked than
in the Chimpanzee, which, however, disappears in aged animals.
It is a curious fact that Gorillas often have a " cleft palate/*
owing to the failure of the palatal part of the palatine bones
to meet completely. The general conformation of the skull is
less braehycephalic in the Gorilla.
The limbs show a number of small differences, which are
associated with a more completely arboreal life in the Chimpanzee
as compared with the Gorilla. The latter is approaching the
human way of life. In spite, however, of these differences, no
hard and fast lines of divergence can be laid down between the
two African Anthropoids, for it appears from the many memoirs
that have been written upon both that "there is scarcely a
feature in any muscle or bone found in one animal which is not
also found in the other." The heel of the Gorilla has already
been referred to. This is, of course, associated with a plantigrade
and therefore non-arboreal mode of progression. Certain of the
muscles of the calf of the leg attached to the heel show a more .
human arrangement in the Gorilla than in the Chimpanzee. It-
is interesting to find that the muscles of the little toe are
diminishing in the Gorilla as in Man. This is most clearly due
to terrestrial progression and we may apply the same explanation
to Man and ignore tight boots! The arm of the Gorilla is less
adapted to arboreal progression. Its proportions differ from those
of the ana of the Chimpanzee in that the fore-arm is shorter. In